Spray 12-inch Dutch oven with vegetable oil cooking spray. Cut or tear the tortillas into bite-sized pieces, if desired, and layer 1/3 in the bottom of the prepared Dutch oven. In a skillet, saute the onion and garlic until translucent. Measure out one cup of the enchilada sauce and set aside. Add the remaining enchilada sauce and green chiles to the skillet. Drain chicken and add to the skillet, breaking up the chicken chunks with a fork. Simmer over low heat for 5 min., stirring occasionally.

Remove from heat and stir in olives. Spoon half of the meat mixture over the tortillas in the Dutch oven. Sprinkle with one cup of the cheese. Layer half of the remaining tortillas over the cheese, cover with the remaining meat mixture. Sprinkle one cup of the cheese. Layer the remaining tortillas on top, then spread on reserved enchilada sauce. Sprinkle top with remaining 1/4 cup of cheese and the chives. Cover the Dutch oven, place over coals and place 10 coals on the lid. Cook for about 30 minutes, or until bubbly and cheese is lightly browned. Serve with sour cream, if desired.